The invention relates to a revetment for a bank, water-retaining retaining structure and the like, comprising elements made of concrete or a similar material resting against each other, which elements are approximately prismatic in the height direction and each have two transverse faces and two longitudinal faces between a top face and a bottom face, which revetment has open spaces extending between the top faces and the bottom faces, for allowing water to pass through.
Such a revetment is known from NL-C-122279. This known revetment is made of identical elements of a polygonal, convex shape. This shape produces a revetment which has open spaces, which has the advantage that at the underside of the revetment no water pressure which would have a tendency to lift the elements can occur. Such a design is advantageous particularly in the case of revetments of a slope of the type which occurs in the case of sea dikes or river banks. Although the water constantly flowing in waves against the slope can enter by way of said open spaces, at the same time it flows back again unimpeded, in such a way that it cannot grip the elements, and the revetment remains intact.
The disadvantage of this known revetment is, however, that the desired ratio between open and closed surface thereof is found only in the straight parts of a slope. As soon as the slope undergoes a curvature, larger open spaces are bound to remain open, owing to the fact that the known elements then no longer butt up well against each other. The larger open spaces could, of course, be reduced by skilled rearrangement or by filling up with smaller pieces, but skilled personnel is required for this, and such personnel are not always available.
The object of the invention is to provide a revetment which, on the one hand, is simple to lay using machines and unskilled personnel and which, on the other hand, still allows the correct ratio between open and closed parts to be achieved, even in curved parts of the slope. That object is achieved by the fact that one transverse face of each element is made a concave shape and the other transverse face is made a corresponding convex shape.
Owing to the concave/convex shape of the elements, said elements can be laid so that they butt up well against each other, even in the curved parts of a slope. Moreover, such an advantageous result can be obtained in the case of various gradients, while quay walls can also be revetted with the elements according to the invention. Owing to the open spaces, water cannot make any impression on the revetment.
The elements form rows in which the transverse sides in each row rest against each other and elements from adjacent rows rest with their longitudinal sides against each other.
The revetment known from NL-C-122279 is made with elements whose transverse faces and/or longitudinal faces are formed in such a way that the elements resting against each other leave spaces clear for allowing water to pass through. In the case of the revetment according to the invention, in addition to the concave/convex shape, it is also possible to use the element shapes according to NL-C-122279, which provide open spaces there.
However, in the case of the revetment according to the invention at least one of the transverse faces and/or longitudinal faces preferably comprises a passage opening, which transverse faces and/or longitudinal faces are formed in such a way that the elements resting against each other leave open spaces clear for allowing water to pass through, while the elements can rest with their transverse faces against each other in various rotated positions, and the passage openings each bound an open space with an opposite wall and/or passage opening of an adjacent element.
As an alternative, the elements can contain a passage opening which does not open onto a transverse face or a longitudinal face.
In particular, the transverse faces of the elements can be of a corresponding round shape parallel to the height direction, preferably corresponding approximately to a part of a cylinder. The longitudinal faces of the elements can be essentially flat, in such a way that they can be laid in half-brick bond or also in brick bond. In this case the elements form rows in which the transverse sides in each row rest against each other.
In order to provide the necessary openings, at least one of the longitudinal faces or transverse faces can have a recess.
The invention also relates to an element for use in the revetment according to the invention.